Method and apparatus for filling containers

ABSTRACT

THE DISCLOSURE RELATES TO A METHOF AND APPARATUS FOR FILLING CONTAINERS WITH PARTICULATE MATERIAL BY AT LEAST PARTIALLY SURROUNDING THE CONTAINER WITH A SHROUD WHICH SEALINGLY ENGAGES THE CONTAINER TO PROVIDE A BARRIER BETWEEN THE SHROUD AND THE MOUTH OF THE CONTAINER. THE CONTAINER IS LOADED INTO A CONTAINER FILLING ZONE, FILLED, AND UNLOADED FROM THE CONTAINER FILLING ZONE WITH THE BARRIER BETWEEN THE SHROUD AND THE CONTAINER, THEREBY PREVENTING CONTAMINATION OF THE SHROUD INTERIOR AND THE CONTAINER EXTERIOR. A DUST COLLECTING SYSTEM IS OPERABLE TO PREVENT CONTAMINATION BY PARTICLE DUST AND PARTICULATE MATERIAL WHILE LOADING AND UNLOADING CONTAINERS INTO AND OUT OF THE FILLING ZONE.

Sept. 20, 1971 c. Fl CARTER METHOD AND AIPARATUS FOR FILLING CONTAINERS 3 Sheets-Sheet 1 Filed Kay 1, 1970 CLARENCE F FIG. 3

BY BMMIDMIW,

Mm monuevs Sept. 20, 1971 c. F. CARTER METHOD AND APPARATUS FOR FILLING CONTAINERS 3 Sheets-Sheet 2 Filed May 1, 1970 FIG. 5

P 30, 1971 c. F. CARTER METHOD AND APPARATUS FOR FILLING CONTAINERS 5 Sheets-Sheet 5 Filed May 1, 1970 TIIm F GE United States Patent Ofice Patented Sept. 20, 1971 U.S. Cl. 141-5 19 Claims ABSTRACT OF THE DISCLOSURE The disclosure relates to a method and apparatus for filling containers with particulate material by at least partially surrounding the container with a shroud which sealingly engages the container to provide a barrier between the shroud and the mouth of the container. The container is loaded into a container filling zone, filled, and unloaded from the container filling Zone with the barrier between the shroud and the container, thereby preventing contamination of the shroud interior and the container exterior. A dust collecting system is operable to prevent contamination by particle dust and particulate material while loading and unloading containers into and out of the filling zone.

BACKGROUND OF THE INVENTION The present invention relates to a method and apparatus for filling containers with particulate material and more specifically relates to a method and apparatus for filling all types and sizes of containers with particulate material utilizing vacuum filling techniques.

The filling of containers with finely divided particulate material utilizing vacuum filling techniques presents a number of problems. Among the more serious problems encountered are the contamination of the air in the area by particle dust and the accumulation of particulate material on the filling apparatus and containers. Such contamination afiects the equipment reliability, the container appearance and the health of those operating the equipment, particularly when filling containers with toxic materials.

Contamination may occur if the seal between the container and the filling apparatus or head is broken while particulate material is being dispensed, particularly when a vacuum exists around the exterior of the container and is greater than a vacuum in the interior of the container as is sometimes the case. Contamination may also occur because of inadequate sealing between the container and the filling head which may be caused by slight dents in the lip of the open mouth of the container.

An additional problem encountered in the vacuum filling of containers is the buckling of containers due to the axial load to which the container must be subjected to prevent the seal between the container and the filling head from breaking while filling the container. This is a particular problem where back flushing is used to clean the screens in the filling head as in the United States Carter Patent 2,815,621. The fluctuations in pressure within the container interior, caused by back flushing the screens, tend to break the seal between the container and the filling head which, if allowed to occur, would cause a loss of material as well as contamination of the exterior of the container and the interior of the shroud. To prevent the breaking of this seal and the resultant contamination, the container walls must be subjected to substantial axial loading, sometimes resulting in the buckling of the container walls.

It is therefore an object of the present invention to provide a novel method and apparatus for filling containers with particulate material with a minimum of contamination thereby resulting in a cleaner, more eificient filling operation.

It is a further object of the present invention to provide a novel method and apparatus for filling containers with particulate material with a minimal loss of material.

It is another object of the present invention to provide a novel method and apparatus for preventing the escape of particle dust into the air into the vicinity of the apparatus while loading and unloading containers.

It is yet another object of the present invention to provide a novel method and apparatus for filling slightly damaged containers with particulate material, without the loss of material and the contamination of the area and the equipment.

It is still a further object of the present invention to provide a novel method and apparatus for filling containers wherein improved airtight seals may be easily provided.

It is yet a further object of the present invention to provide a novel method and apparatus for filling containers with particulate material which minimize the buckling of the container during the filling operation.

It is still another object of the present invention to provide a novel method and apparatus for filling containers of a variety of types and sizes, including solid and flexible walled containers, with particulate material.

These and other objects and advantages of the present invention will become apparent from a perusal of the detailed description read in conjunction with the accompanying drawings.

SUMMARY OF THE INVENTION A first significant method aspect of the present invention involves at least partially surrounding a container with a shroud which cooperates with the container to provide a barrier between the shroud and the open mouth of the container, moving the shroud, while retaining the surrounding relationship and the barrier between the shroud and the container into sealing engagement with a filling head, filling the container with particulate material and, while retaining the surrounding relationship and the barrier between the shroud and the container, removing the shroud and the container from engagement from the filling head.

Another significant aspect of the present invention is the provision of a novel combination of apparatus means to accomplish, in coordinated relation, the various steps of the first method above described.

A second significant method aspect of the present invention involves at least partially surrounding the exterior periphery of a container with a generally openended shroud having a member at one end thereof to sealingly engage the open mouth of the container thereby providing a barrier between the shroud and the open mouth of the container, moving the shroud and container into a container filling zone, moving the shroud into sealing engagement with the filling head while retaining the surrounding relationship and the sealing engagement between the shroud and the container, filling the container with particulate material, removing the shroud and container from the container filling zone, and removing the shroud from surrounding relationship and sealing engagement with the container.

A further significant aspect of the present invention is the provision of a novel combination of apparatus means to accomplish, in coordinated relation, the various steps of the second method above described.

A third significant method aspect of the present invention involves creating a vacuum in the interior of a container filling zone through a screen means and admitting particulate material into the interior of the container, intermittently admitting a limited quantity of air through the screen means into the interior of the container to clean the screen means, interrupting the creation of the vacuum in the container interior, admitting air into the container through the screen means until the interior of the container is at atmospheric pressure, interrupting the admission of air through the screen means, and, while unloading the container from the container filling zone and while loading a different container into the container filling zone, applying a relatively low vacuum to the screen means to remove particle dust from the container filling zone and to hold accumulated particulate material on the screen means.

A further aspect of the present invention is the provision of a novel combination of apparatus means to accomplish, in coordinated relation, the various steps of the third method above described.

A fourth significant method aspect of the present invention involves various novel combinations, in coordinated relation, of the steps of the methods previously described.

Yet another significant aspect of the present invention is the provision of a novel combination of apparatus means to accomplish, in coordinated relation, the various steps of the novel combinations of the methods above described.

THE DRAWINGS FIG. 1 is an elevation in partial section of the container filling apparatus of the present invention showing a shroud and a container in the filling position;

FIG. 2 is an enlarged view of a portion of the top of the shroud in the apparatus of FIG. 1;

FIG. 3 is an enlarged view of a portion of the top of the shroud in the apparatus of FIG. 1 shown in surrounding relationship and sealing engagement with a container and in sealing engagement with a filling head;

FIG. 4 is an enlarged view of a portion of the bottom of the shroud in the apparatus of FIG. 1;

FIG. 5 is a plan view of the filling apparatus of FIG. 1;

FIG. 6 is a schematic representation of an elevation of the filling head utilized in the apparatus of FIG. 1; and,

FIG. 7 is an elevation of a container filling system employing the container filling apparatus of FIG. 1. and operable in accordance with the methods of the present invention.

DETAILED DESCRIPTION Filling apparatus Referring now to the drawings, and specifically to FIG. 1, the filling apparatus of the present invention comprises a support frame 1 having a plurality of vertical members 10 which are interconnected by a plurality of transverse members 12 at the lower ends thereof. At the upper ends of the vertical members 10, a support plate 14 is provided to interconnect the upper ends of the vertical members 10 and to provide a support for a filling head 16.

The support frame is preferably mounted on a weight responsive base comprising a horizontally disposed frame 18 having two vertically disposed frame support members 20 and a vertically disposed weight responsive ele ment 22. The frame support members 20 preferably include a vertical beam 24 at the top of which is provided a solid cylindrical member 26, the upper end of which is semi-spherical in shape. The weight responsive element 22 may comprise a conventional load cell having a load receiving member 28 which supports the load and causes the load cell to produce an output signal proportional to the weight of the load applied thereto. The end of the load receiving member 28 is likewise semispherical in shape.

Three pads 30 are provided on the underside of the transverse members 12 to pivotally engage the ends of the cylindrical members 26 and the load receiving member 28. Each of the pads 30 is provided with a semi spherical depression 32 to receive the similarly shaped ends of the cylindrical member 26 and the load receiving member 28. The entire filling apparatus is thus supported on a three point, ball-in-socket type suspension, thus allowing non-restricted pivotal movement of the apparatus as the load cell is depressed in response to an increase in weight during filling.

Further, as illustrated in FIG. 5, the three pivot points provided by the frame support members 20 and the weight responsive element 22 are radially equidistant from a vertical line passing through the approximate center of gravity of a loaded container filling apparatus, i.e. the container filling apparatus with a container positioned for filling as shown in FIG. 1. Due to the relatinship, approximately one third of the total weight of the apparatus is felt at the load receiving member 28 of the weight responsive element or load cell 22.

Referring once again to FIG. 1, an air cylinder 34, supported by the transverse members 12, is connected by way of a piston rod 36 to a substantially flat, horizontally disposed support member or platform 38 which is free to reciprocate vertically in response to the application of air pressure to the cylinder 34.

A vacuum conduit 40 and a pressurized air conduit 42, connected to the underside of the platform 38, communicate, by way of openings 44 and 46, respectively, with the upper side of the platform 38. The conduits 40 and 42 are connected, respectively, to a suitable means for creating a vacuum, e.g. a vacuum pump, and a suitable supply of air pressure, eg the atmosphere (not shown). Suitable remotely controlled valves 48 and 50 are provided in the conduits 40 and 42 respectively to control the fiow of air therethrough in response to appropriate control signals.

The filling head 16 is mounted above the platform 38 and preferably includes a generally fiat, circular plate 51 having a centrally disposed opening 52 extending axially therethrough, i.e. along the axis of the plate 51 normal to the surface thereof, and first and second annular concentric grooves 54 and 56, respectively, disposed in the underside of the plate 51. An annular screen 58, generally parallel to the lower surface of the plate, is secured across the first annular groove 54 in a suitable, conventional manner. Disposed in the second annular groove 56 is a generally flat annular sealing gasket 60, the outer surface of which is generally parallel to and flush with the lower surface of the plate 51.

The annular screen 58 may be any suitable screen which permits the passage of air while preventing the passage of particulate materials. Such screens are entirely conventional and are well known in the art to which the present invention relates.

The sealing gasket 60 preferably has a sponge rubber base 60A covered by a relatively thin layer of gum rubber 60B on the outwardly facing surface thereof, as illustratcd in FIG. 3. This arrangement provides the necessary resilience as well as a durable sealing surface. Additionally, the sealing gasket 60 preferably provides a sufiiciently wide sealing surface in the underside of the filling head 16 to accommodate a wide range of shroud and therefore container sizes.

A plurality of openings 62 are provided through the plate 51 of the filling head 16 to provide communication between the upper surface of the plate 51 and the first annular groove 54. Each opening 62 is connected to an associated conduit which will hereinafter be described in connection with the operation of the filling head 16. In addition, since the openings 62 communicate with the first annular groove 54 which is covered by the annular screen 58, the openings 62 will hereinafter be referred to as screened openings.

It should be understood that the filling head 16 as described above is a preferred embodiment of the filling head of the present invention and is adapted to be used in connection with the filling of generally cylindrical containers. The head and groove shapes may, of course, be varied to allow the filling of other container shapes without departing from the spirit of the present invention.

As illustrated in FIG. 1, the filling apparatus also includes an air cylinder 64 connected to a transverse brace 66 and having a curved plate 68 connected to the piston rod thereof. The cylinder 64 is mounted so that the direction of the stroke of the piston is substantially perpendicular to the vertical axis of the filling apparatus. On the opposite side of the filling apparatus, a horizontally disposed roller 70 is provided to facilitate the loading and unloading of the filling apparatus.

Referring now to FIGS. 1 through 4, a container 72, surrounded by and in sealing engagement with a shroud 74, as will hereinafter be described, may be positioned within the filling apparatus in a filling zone generally defined by the filling head 16, the platform 38 and the vertical member 10, as illustrated.

The shroud 74 is preferably a substantially open-ended cylinder, having a slightly larger diameter than the container 72 and generally conforming in shape to the shape of the exterior periphery of the container 72. The shape of the shroud may, of course, be varied to permit the filling of a variety of container shapes without departing from the spirit of the present invention.

An inner sealing member 76, preferably carried by the shroud 74, is provided between the interior periphery of the upper end of the shroud 74 and a peripherally extending edge 78 defining an open mouth of the container 7 2.

As shown in FIG. '3, the inner sealing member 76 is operable to resiliently deform so as to conform to the shape of the peripherally extending edge 78 and is thus adapted to engage the edge 78' of the container 72 to provide a substantially airtight seal between the top of the shroud 74 and the edge 78 defining the open mouth of the container 72. This seal provides a barrier between the upper portion of the shroud 74 and the edge 78 of the container 72, thereby preventing the contamination of the interior of the shroud and the exterior of the container by particulate material.

As will subsequently be described, the shroud 74 and the container 72 are loaded together into the filling zone, while in surrounding relationship and sealing engagement, from a conveyor 80 adjacent the platform 38 of the container filling apparatus. Since the shroud 74 and the container 72 remain in surrounding relationship and sealing engagement during the filling of the container 72 and during the unloading of the shroud 74 and the filled container 72 from the filling zone onto the conveyor 80 after the filling operation, the protective barrier formed by the inner sealing member 76 is operable to prevent the contamination of the interior of the shroud 74 and the exterior of the container 72 while loading, filling, and unloading the container 72. The importance of the prevention of contamination is quite apparent from the standpoint of appearance of the container 72 after filling and the continued efficient operation of the filling apparatus. However, it becomes extremely important to prevent such contamination when handling particulate materials which are toxic.

While the inner sealing member 76 could be provided on the edge 78 of the container 72, the inner sealing member 76 is preferably carried by the shroud 74, as previously described and as illustrated in FIGS. 2 and 3. This arrangement allows the filling apparatus of the present invention to be utilized with commercially available containers.

Referring now to FIGS. 2 and 3, the preferred inner sealing member 76 comprises an annular ring-like member 82 connected to the interior of the shroud 74 to form an inwardly projecting shoulder around the interior periphery of the top of the shroud 74. As illustrated, the uppermost portion of the annular ring-like member 82 is provided with a sharp corner or edge 84 to provide an airtight seal when the shroud 74 is raised to the filling position and the ring-like member 82 engages the sealing gasket in the filling head 16. An annular, resilient inner sealing gasket 86, operable to deform from the flat face configuration of FIG. 2 to conform to the shape of the edge 78 defining the open mouth of the container 72 as shown in FIG. 3, is carried by the ring-like member 82 in an annular groove 88 in the lower surface thereof. The inner sealing gasket 86 is preferably made of soft sponge rubber to permit vertical movement of the container 72 without causing excessive stress in the walls thereof, and to make allowance for slight variations in container height. As illustrated in FIG. 3, the inner sealing gasket 86 also provides a seal which extends around the sides of the edge 78 to protect against air leaks between the interior and exterior of the container 72 due to the irregular shape or damage to the top of the edge 78 defining the open mouth of the container 72.

Referring now to FIGS. 1 and 4, the shroud 74, in surrounding relationship with the container 72 and in sealing engagement with the edge 78 defining the open mouth thereof, is carried by the platform 38 while filling the container 72. Since a vacuum must be created in the space between the interior of the shroud 74 and the exterior of the container 72 to prevent the inward collapse of the wall of the container 72 when a vacuum is created in the interior of the container 72 during the filling operation, an outer sealing member 90 is provided between the bottom of the shroud 74 and the upper surface of the platform 38. The outer sealing member 90 cooperates with the inner sealing member 76 to provide a substantially airtight chamber between the interior periphery of the shroud 74 and the exterior periphery of the container 72 as illustrated in FIG. 1.

The outer sealing member 90 may be carried by either the platform 38 or the shroud 74. However, in the preferred embodiment of the present invention, the outer sealing member 90 is carried by the shroud 74 and comprises a resilient outer sealing gasket 91 carried by a flange 92 on the bottom exterior periphery of the shroud 74. The outer sealing gasket 91 extends slightly below the flange 92 and is angled outwardly and downwardly from the wall of the shroud 74 to provide airtight engagement with the platform 38. In addition, the portion of the outer sealing gasket 91 abutting the platform 38 may be rounded as illustrated to prevent the outer sealing gasket 91 from scuffing against obstacles which may be encountered during the loading and unloading of containers.

Filling head As previously described in connection with FIG. 1, the filling head 16 is provided with a centrally disposed opening 52 providing communication between the top and the underside of the filling head 16, and a plurality of openings 62 providing communication between the top of the filling head and the first annular groove 54 in the bottom surface of the filling head 16.

Referring now to FIGS. 5 and 6, the filling head 16 may be a split filling head of the type disclosed in US. Patent No. 2,954,203, assigned to the assignee of the present invention and may be divided into two substantially identical halves A and B along a line 66 for the purpose of description. Screen frame members 55 and 57 extending between the screen 58 and an inner surface 59 of the groove 54 may be provided across the groove 54 to divide the groove 54 into two separate compartments, one in each half of the filling head 16. A material supply conduit 100, in fluid communication with the opening 52 which is common to both the A and B halves of the filling head 16, is connected to a supply of particulate material. A suitable valve 102 is provided in the material supply conduit to control the flow of particulate material through the conduit. The valve 102 may be any cornmercially available valve suitable for controlling the flow of particulate material in response to electrical, pneumatic or hydraulic signals.

As shown in FIG. 6, pressure conduits 104A and 104B vacuum conduits 106A and 106B and dust collector conduits 108A and 108B, each in fluid communication with an associated one of the screened openings 62 in the respective halves of the filling head 16, are provided. The pressure conduits 104A and 104B may be connected to a suitable source of pressure, e.g. atmospheric pressure, the vacuum conduits 106A and 106B may be connected to a conventional means for creating a vacuum, e.g. a vacuum pump, and the dust collector conduits 108A and 10813 may be connected to a conventional dust collector such as a cyclone dust collector or other low vacuum source. Flow through each of the conduits 104A through 108A and 104B through 108B may be selectively controlled by suitable conventional valves 110A through 114A and 110B through 1148, respectively, although it should be noted that flow through the dust collector conduits 108A and 108B may be controlled by a single valve since flow through both dust collector conduits 108A and 108B will be initiated and interrupted simultaneously during a filling operation.

Overall filling system Before describing the cycling sequence of the control valves associated with the filling head 16, the overall container filling system will be generally described in connection with FIG. 7, wherein the same numbers have been given to previously described elements.

Referring now to FIG. 7, the container filling apparatus is illustrated with the platform 38 in the down position, ready to be loaded with a container 72 for filling, as shown in phantom. However, prior to moving a container onto the platform 38, a shroud 74 must be moved into surrounding relationship and sealing engagement with the container 72. This may be accomplished either manually or automatically by a hoist or other lifting device capable of moving the shroud 74 along a vertical path with substantial accuracy.

The preferred device for accomplishing this movement is illustrated in FIG. 7 and comprises an inflatable member 200 generally conforming to the shape of the outer periphery of the shroud 74 and an air cylinder 202, the piston rod 204 of which is connected through a suitable linkage 206 and a guide member 208 to a retaining member 210 to which the inflatable member 200 is secured.

The guide member 210 slidably engages a vertically disposed rod 212, secured to a suitable framework, and is driven by the air cylinder 202 along a vertical path defined by the rod 212. An air line 214 provides communication between a high pressure air source (not shown) and the inflatable member 200. The application of high pressure air to the inflatable member 200 may be controlled either manually or automatically by a suitable conventional valve (not shown) to thereby selectively control the clamping of the shroud 74 by the inflatable member 200.

In operation, air pressure may be continuously applied, by way of the air line 214, to the inflatable member 200 to provide continuous clamping of the shroud 74 when the hoist is in the up position. When the container 72 is in position, the air cylinder 202 may be manually or automatically actuated to lower the shroud 74 over the container 72. The air pressure applied to the inflatable member 200 may then be released to thereby release the shroud, and the air cylinder 202 may be actuated to raise the hoist from the vicinity of the shroud.

After the container 72 has been filled and the container 72 and shroud 74 are again on the conveyor 80, the inflatable member 200 may be lowered over the shroud 74 by actuating the air cylinder 202. The inflatable mem ber 200 may then be inflated to clamp the shroud exterior, and the shroud 74 may be raised from surrounding relationship and sealing engagement with the container 72 by actuating the air cylinder 202.

Other mechanically or electromagnetically operated hoists may be utilized to provide a means for moving the shroud 74 into and out of surrounding relationship and sealing engagement with the container 72. However, the preferred lifting device will accommodate shrouds of various sizes since the inflatable member 200 can be expanded and contracted over a considerable range, thereby providing flexibility in the container sizes which may be accommodated utilizing the filling system of the present invention.

Operation The operation of the filling system of the present invention will be described in connection with FIGS. 1 and 5 through 7. Referring first to FIG. 7, the container 72 is conveyed to a predetermined position adjacent the filling apparatus and beneath the shroud 74. The air cylinder 202 is actuated to lower the shroud into surrounding relationship with the container 72 and also into sealing engagement with the edge 78 defining the open mouth of the container 72 as illustrated in FIG. 1.

Suitable, conventional inwardly biased guides 81 may be provided in at least three places around the interior periphery of the shroud 74 to insure proper engagement between the edge 78 of the container 72 and the inner sealing member 76 when the shroud 74 is lowered. For example, as illustrated in FIG. 3, three spring biased buttons 83 connected to the interior periphery of the shroud 74 at approximately 120 intervals may be provided. These guides tend to center the container 72 within the shroud 74 thereby insuring proper engagement.

The air pressure applied to the inflatable member 200 is released and the cylinder 202 is actuated to remove the hoist from the vicinity of the shroud 74. The curved plate 68 connected to the air cylinder 64 may then be extended into contact with the exterior surface of the shroud 74 and coupled thereto, utilizing a vacuum or other suitable coupling means. The shroud 74, while in surrounding relationship and in sealing engagement with the container 72, may then be pulled onto the platform 38, as illustrated in phantom, through retraction of the piston of the cylinder 64.

Alternatively, an air cylinder 216, having a curved, piston rod carried plate 218 generally conforming to the shape of the exterior periphery of the shroud 74, may be utilized to push the shroud and container onto the platform 38. The roller 70, the surface of which preferably extends slightly above the surface of the conveyor 80 and the surface of the platform 38, aids in transferring the shroud and container from the conveyor 80 onto the platform 38.

When the shroud and container are positioned within the container filling zone on the platform 38, the coupling force between the curved plate 68 and the shroud 74 is released, and the air cylinder 34 is actuated to raise the shroud 74, surrounding the container 72, into sealing engagement with the sealing gasket 60 in the filling head 16 as previously described. The air cylinder 34 applies a continuously upward bias to the shroud 74 to ensure proper sealing between the shroud 74 and the filling head 16. Since the shroud 74 is interposed between the platform 38 and the filling head 16 and the container 72 is interposed between the resilient, sponge rubber inner sealing gasket 86 and the platform 38, the shroud 74 accepts substantially all of the axial stress produced between the platform 38 and the filling head 16.

After the shroud 74 is sealed against the filling head 16, the dust collector valves 114A and 114B, which are open from the previous filling cycle, are closed, and a vacuum is created in the container 72 by opening the valve 112A and in the space between the interior periphery of the shroud 74 and the exterior periphery of the container 72 by opening the valve 48 in the vacuum conduit 40 beneath the platform 38.

When the vacuum in and around the container 72 has reached a predetermined value, preferably between 10 and 25 inches of mercury, the fill valve 102 in the material supply conduit 100 opens for a predetermined and controlled period, and a first predetermined amount of particulate material is dispensed into the container 72. The vacuum valve 112A closes and the vacuum valve 112B opens. The pressure valve 110A then opens for a period of time sufiicient to drop the vacuum in the container interior about to inches of mercury, thereby causing a flow of air into the container through the screen 58 on the A side of the filling head 16, removing particulate material which has accumulated thereon. This momentary flow of air through the screen 58 for cleaning purposes is preferably always insufiicient to drop the vacuum in the container 72 to zero vacuum, i.e. at atmospheric pressure.

After the pressure valve 110A has been closed for a sufiicient time to permit recovery of the vacuum in the container interior to the predetermined value between 10 and 25 inches of mercury, the fill valve 102 is again opened to dispense a predetermined amount of material into the container 72. When the first predetermined amount of material has been dispensed, the fill valve 102 is again closed as is the vacuum valve 112B. The vacuum valve 112A is then opened and the pressure valve 110B is opened long enough to drop the vacuum in the container about 5 to 10 inches of mercury to clean the screen 58 on the B side of the head in the manner previously described.

This alternate operation of the A and B sides of the head 16 is continued until a predetermined weight of material, as determined by the weight responsive element or load cell 22, has been dispensed, at which time all valves are closed. The pressure valves 110A and 110B in the filling head 16 and the valve 50 in the pressure conduit 42 beneath the platform 38 are opened to relieve the vacuum in and around the container 72. The cylinder 34 is actuated to lower the shroud 74 and the container 72 and, just as the seal between the shroud 74 and the filling head 16 is broken, the pressure valves 110A and 110B and the pressure valve 50 are closed and the dust collector valves 114A and 114B in the dust collector conduits 108A and 108B are opened providing a relatively low suction in the vicinity of the underside of the filling head 16 and the top of the container 72 and the shroud 74. Since the pressure valves 110A and 110B are closed to prevent the fiow of air through the pressure conduits 104A and 104B, the suction tends to collect any dust in the air exteriorly of the groove 54 and tends to either hold the dust against the screen 58 or transmit the dust to a suitable conventional dust collector. The suction additionally prevents material which has accumulated on the screen 58 during the filling operation from dropping onto the platform 38 and into the filling zone when the shroud 74 and container 72 are removed therefrom.

When the platform 38 reaches the down position, the air cylinder 64 is actuated and the shroud, still in surrounding relationship and in sealing engagement with the container 72, is pushed onto the conveyor 80. The inflatable member 200 is then lowered over the shroud 74 and is inflated to engage the exterior periphery of the shroud 74. The shroud is then raised clear of the container 72 and the conveyor 80 transports the full container away while simultaneously transporting an empty container to the predetermined position adjacent the filling apparatus and beneath the shroud 74.

The dust collector valves 114A and 114B remain open until a container and shroud have been moved into the filling apparatus and have been raised into sealing engagement with the filling head 16. These valves are then closed' prior to the commencement of the creation of a vacuum in the space in and around the container 72. Thus, any material which has been held against the screen 58 by the flow of air through the dust collector conduits 108A and 108B is retained against the screen 58 at all times during the loading and unloading of the filling apparatus and is allowed to drop until the shroud 74 is sealed against the filling head 16. In addition, the suction created by the dust collector aids the cylinder 34 in sealing the shroud 74 against the filling head 16 thereby permitting the use of a smaller cylinder 34 than would otherwise be required.

In summary, the sequence for filling containers with the system of the present invention is as follows:

Sequence (1) Convey an empty container 72 to a predetermined position adjacent the filling apparatus and beneath the shroud 74;

(2) Lower the shroud 74 into surrounding relationship and sealing engagement with the container 72;

(3) Push (or pull) the shroud 74 surrounding the container 72 onto the platform 38 of the filling apparatus;

(4) Raise the platform 38 until the top of the shroud 74 is in sealing engagement with the filling head 16;

(5) Open the vacuum valve 112A in the filling head 16 and the vacuum valve 48 in the platform 38 to create a vacuum of between 10 and 25 inches Hg in the interior of the container 72 by drawing air out of the container through the screen 58 and in the space between the shroud and the container by drawing air through the opening 44 in the platform 38;

(6) Open the material supply valve 102 in the filling head 16 to admit particulate material into the container 72;

(7) Interrupt the material supply after a first predetermined amount of material has been dispensed;

(8) Close the vacuum valve 112A and open the vacuum valve 112B in the filling head 16;

(9) Open a pressure valve 110A in the filling head to admit a limited quantity of air, insufficient to drop the vacuum in the container interior to zero, into the container interior through the screen 58 to clean material off the screen;

(10) Repeat steps (6) through (9) alternating from the A to the B side of the filling head 16 until a predetermined total amount of material has been dispensed;

(11) Close the vacuum valves 112 and 48 in the filling head 16 and in the platform 38, respectively (12) Open the pressure valve 110A or 110B in the filling head and the pressure valve 50 in the platform 38 to admit air into the container interior and into the space between the shroud 74 and the container 72 to relieve the vacuum in and around the container;

(13) Break the seal between the shroud 74 and the filling head l6;

(14) Close the pressure valves 110 and 50 in the filling head and in the platform respectively and open the dust collector valves 114A and 114B in the filling head 16 just as the seal between the shroud 74 and the filling head 16 is broken to collect dust and to hold material against the screen 58;

(15) Push (or pull) the shroud 74 still surrounding the full container 72 onto the conveyor belt (16) Raise the shroud 74 from surrounding relationship and sealing engagement with the container 72;

(17) Convey the full container 72 away from the filling apparatus while simultaneously conveying an empty container 72 to the position adjacent the filling apparatus;

(18) Lower the shroud 74 over the empty container 72;

(19) Push (or pull) the shroud 74 and the container 72 onto the platform 38;

(20) Raise the platform 38 to seal the shroud 74 against the filling head 16;

(21) Close dust collector valves 114A and 114B and repeat steps (5)(2l), inclusive.

While the system of the present invention has been described in connection with the filling of solid-walled containers, such as pressed paper or plastic containers, with out the use of an impervious bag liner, a liner may be inserted if desired. For example, after the shroud 74 has been lowered into surrounding relationship and sealing engagement with the container 72, an impervious bag iiner may be inserted into the interior of the container 72 with the top of the liner drawn over the top edge of the shroud 74 as illustrated in phantom in FIG. 3. Air may be removed between the liner and the interior of the container 72 utilizing a system such as that described in the previously referenced United States patent. Additionally, the shape of the inner sealing member 76 may be altered in a manner well known in the art to prevent air leakage around the top of the shroud 74 when filling lined containers with the system of the present invention.

The present invention may also be employed to fill containers such as plastic bags without the use of a solidwalled container. As shown in phantom in FIG. 3, the bag may be inserted into the shroud 74 with the open mouth thereof drawn over the top edge of the sealing member 76. The container 72 need not be utilized, in which case the bag may be filled in the same manner in which a solid container is filled. The previously described barrier between the shroud 74 and the container is provided, when filling bags, by the cooperation between the open mouth of the bag container and the edge 84 of the sealing member 76.

It is apparent from the above description of the filling system of the resent invention that the exterior of the container 72 and the interior of the shroud 74 are always shielded from contamination by particulate material during the loading, filling and unloading of the container 72, resulting in a minimal loss of material and a cleaner more efficient and other improved container filling system. Contamination of the equipment and the space in the vicinity thereof is also prevented by the method and apparatus of the present invention.

It is further apparent that the present invention allows a great variety of types and sizes of containers to be filled, even where slight container irregularity or damage has occurred.

In addition, the present invention provides improved sealing with a minimum of container buckling in a relatively simple manner. The improved seating is aided by suction created by the dust collector and by the vacuum between the shroud and the container during filling since both the suction and the vacuum tend to raise the upwardly biased platform 38 which in turn increases the sealing force between the shroud 74 and the filling head 16. Container buckling is minimized since the shroud accepts most of the axial load between the platform 38 and the filling head 16. Also, since the vacuum around the outside of the container is always equal or exceeds the vacuum in the interior of the container, inward container buckling due to pressure differentials is eliminated.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed is:

1. Apparatus for filling open mouth containers with particulate material comprising:

a filling head;

a support member for carrying a container during a filling operation;

a substantially open-ended shroud carried by said support member and at least partially surrounding the exterior periphery of the container;

first sealing means carried by one of said shroud and the container;

second sealing means carried by one of said shroud and said support member;

said first sealing means cooperating with the container 12 to provide a barrier between said shroud and the container to prevent the contamination of the interior of said shroud and the exterior of the container during filling, loading and unloading;

said first sealing means cooperating with said filling head to provide a substantially airtight seal between the exterior of said shroud and the interior of the container; and,

said first and second sealing means cooperating to provide a substantially airtight chamber between the interior of said shroud and the exterior periphery of the container.

2. The apparatus of claim 1 wherein said filling head comprises:

a generally flat plate having a centrally disposed aperture extending axially therethrough;

a first groove outwardly displaced from said aperture in one surface of said plate;

a plurality of openings communicating with said first groove from the other surface of said plate;

a screen disposed generally parallel to said one surface of said plate and extending across said groove; and,

in said one surface of said plate, a second groove substantially concentric with and outwardly displaced from said first groove, said second groove containing a resilient sealing member generally conforming to the shape of the top edge of said shroud.

3. The apparatus of claim 1 further comprising:

means carried by said filling head for creating a vacuum in the container; and

means carried by said support member for creating a vacuum in said substantially airtight chamber.

4. The apparatus of claim 1 wherein said first sealing means is carried by said shroud and includes:

a resilient gasket deformable to conform to the shape of the peripherally extending edge defining the open mouth of the container and to sealingly engage the top and the sides of said edge; and,

means for sealingly engaging said filling head.

5. The apparatus of claim 2 further including:

a material supply conduit in fluid communication with said centrally disposed aperture;

a vacuum conduit, a pressure conduit, and a dust collector conduit, each in fluid communication with an associated one of said plurality of openings; and,

means for selectively controlling flow through said conduits.

6. The apparatus of claim 4 including a resilient sealing member carried by said filling head and generally conforming to the shape of the top peripheral edge of said shroud, said sealing member being less resilient than said resilient gasket to allow said shroud to accept substantially all of the axial load produced between said support member and said filling head during a filling operation.

7. Apparatus for filling, with particulate material, containers having a peripherally extending edge defining an open mouth, the apparatus comprising:

a filling head;

a support member for carrying a container during a filling operation;

an open-ended shroud carried by said support member and surrounding the exterior periphery of the container;

first sealing means carried by one of said shroud and the container;

said first sealing means being operable to provide a barrier between said shroud and the peripherally extending edge of the container to prevent-the contamination of the interior of said shroud and the exterior of the container by particulate material while filling, loading and unloading the container;

second sealing means carried by one of said shroud and said support member;

said first and second sealing means cooperating to provide a substantially airtight chamber between the interior of said shroud and the exterior periphery of the container; and

means for moving said shroud, while in surrounding relationship and sealing engagement with the container, into substantially airtight sealing engagement with said filling head.

8. The apparatus of claim 7 wherein said filling head comprises:

a generally fiat plate having a centrally disposed aperture extending axially therethrough;

a first groove outwardly disposed from said aperture in one surface of said plate;

a plurality of openings communicating wth said first groove from the other surface of said plate;

a screen disposed generally parallel to said one surface of said plate and extending across said groove; and,

in said one surface of said plate, a second groove substantially concentric with and outwardly displaced from said first groove, said second groove containing a resilient sealing member generally conforming to the shape of the top edge of said shroud.

9. The apparatus of claim 7 further comprising:

means carried by said filling head for creating a vacu um in the container; and,

means carried by said support member for creating a vacuum in said substantially airtight chamber.

10. The apparatus of claim 7 wherein said first sealing means is carried by said shroud and includes:

a resilient gasket deformable to conform to the shape of the peripherally extending edge defining the open mouth of the container and to sealingly engage the top and the sides of said edge; and,

means for sealingly engaging said filling head.

11. The apparatus of claim 8 further including:

a material supply conduit in fluid communication with said centrally disposed aperture;

a vacuum conduit, a pressure conduit, and a dust collector conduit, each in fluid communication with an associated one of said plurality of openings; and

means for selectively controlling flow through said conduits.

12. The apparatus of claim 10 including a resilient sealing member carried by said filling head and generally conforming to the shape of the top peripheral edge of said shroud, said sealing member being less resilient than said resilient gasket to allow said shroud to accept substantially all of the axial load produced between said support member and said filling head during a filling operation.

13. Apparatus for filling with particulate material, containers having an upper portion defining an open mouth, the apparatus comprising:

filling means operable to transmit particulate material;

support means adapted to support a container beneath said filling means;

a substantially open-ended shroud adapted to at least partially surround the exterior periphery of the container, said shroud being adapted to be carried by said support means;

sealing means adapted to be connected between said shroud and an upper container portion defining an open month, said sealing means being operable to provide a barrier between said shroud and said container while filling, loading and unloading the container to prevent the contamination of the interior of said shroud and the exterior of the container by particulate material; and

means for raising said support means and said shroud,

with said shroud being in at least partially surrounding relation to the exterior periphery of the container, to bring said container into filling cooperation with said filling means.

14. Apparatus for filling open mouth containers with particulate material comprising:

intermittently operable conveyor means for transporting a container to a predetermined position adjacent a filling apparatus;

a substantially open-ended shroud having a first resilient sealing means disposed around the interior periphery of one end thereof, and a second resilient sealing means disposed around the exterior periphery of the other end thereof, said shroud being operable to surround the exterior periphery of the container and said first sealing means being operable to provide a barrier between the interior periphery of said one end of said shroud and the edge of the open month of the container;

means for moving said shroud into surrounding and barrier providing relationship with the container;

means for moving said shroud, while in surrounding and barrier providing relationship with the container, onto a support member positioned beneath a filling head, said second sealing means cooperating with said support member and said first sealing means cooperating with said container to provide a substantially airtight chamber between said shroud and the container on the support member;

means for raising said shroud, while in surrounding and barrier providing relationship with the container, into airtight engagement with said filling head;

means carried by said support member for creating a vacuum in the space between said shroud and the container;

means carried by said filling head for creating a vacuum in the container;

means for filling the container with a predetermined amount of particulate material; and,

means for moving said shroud while in surrounding and barrier providing relationship with the container, onto said conveyor means after the container has been filled.

15. The apparatus of claim 14 wherein said filling head includes:

a centrally disposed material supply conduit;

a screened vacuum conduit;

a screened pressure conduit;

a screened dust collector conduit;

said conduits communicating with a filling zone beneath said filling head;

said screened conduits being radially displaced from said supply conduit; and,

means for selectively controlling fiow through said conduits.

16. In a method of filling open mouth containers with particulate material within a vacuum filling apparatus including a filling head and a container filling zone between a support member and the filling head, the steps of:

(a) surrounding at least a portion of the exterior periphery of a container with a generally open-ended shroud having a member at one end thereof to sealingly engage the open mouth of the container thereby providing a barrier between the shroud and the open mouth of the container.

(b) moving the shroud, while in at least partially surrounding relationship and in sealing engagement with the container, into a container filling zone;

(c) moving the shroud, while in at least partially surrounding relationship and in sealing engagement with the container, into engagement with the filling head;

( d) filling the container with particulate material;

(e) removing the shroud, while in at least partially surrounding relationship and in sealing engagement with the container, from the container filling zone; and,

(f) removing the shroud from at least partially surrounding relationship and sealing engagement with the container.

17. The method of claim 16 wherein the step of filling the container with particulate material includes the step of: creating a vacuum in the interior of the container 15 and in the space between the container and the shroud to increase the effectiveness of the engagement between the filling head and the shroud and to allow the container to be filled by a vacuum filling technique without buckling the container walls.

18. The method of claim 16 wherein the step of removing the shroud, while in surrounding relationship and in sealing engagement with the container, from the container filling zone includes the steps of:

(1) breaking the engagement between the shroud and the filling head; and,

(2) immediately creating a fiow of air through the filling zone to collect dust in the filling zone and to prevent particulate material from contaminating the filling apparatus While unloading the container from the filling zone and while loading a different container into the filling zone.

19. In a method of filling open mouth containers with particulate material within a vacuum filling apparatus including a support member for carrying containers durin g the filling operation disposed beneath a vacuum filling head, the steps of:

(a) positioning a generally open-ended shroud in surrounding relationship with the exterior periphery of an empty container and in sealing engagement the shroud and at least a portion of the exterior periphery of the container;

(e) admitting particulate material into the container while continuously maintaining the vacuum in the container and the chamber;

(f) interrupting the flow of material into the container when a predetermined amount of material has been dispensed;

(g) admitting a limited quantity of air into the container, the quantity of air being insufl'lcient to increase the pressure in the container to atmospheric;

(h) repeating steps (e) through (g) until a predetermined amount of material has been dispensed;

(i) opening a valve in the filling head to entirely relieve the vacuum in the container interior and the chamber;

(j) closing the valve in the filling head;

(k) lowering the support member to break the seal between the shroud and the fililng head;

(1) creating a suction in the vicinity of the open mouth of the container and the underside of the filling head to collect dust created during the filling operation;

(m) removing the shroud, while in surrounding relaship and in sealing engagement with the container, from the support member onto the conveyor; and,

(n) removing the shroud from surrounding relationship and sealing engagement with the container.

References Cited UNITED STATES PATENTS 2,690,865 10/1954 Fischer et al l415l HOUSTON S. BELL, JR., Primary Examiner US. Cl. X.R.

l4l5l, 93, 282, 286, 371, 390 

